Effect of adding vermicompost extract and spraying with nano iron and boron on the vegetative traits of papaya trees (Carica papaya L.)

Abstract

. The field study was conducted at Al-Musauib Papaya Orchard in October 2024 and June 2025. This study was carried out to assess the effect of vermicompost extract and the application of nano iron/boron foliar sprays on the fruit's mineral content. The experiment was arranged in complete randomized blocks with three factors and three replications each. The factors are vermicompost extract at 0.50 ml/L with two levels, nano boron at 0, 5, 15, and 10 mg/L, and nano iron at 0, 2, 4, and 6 mg/L. The significant findings of this experiment are as follows: the treatment with vermicompost at 50 ml/L gave the largest leaf area at 153.67 cm², the tallest stem at 403.77 cm, the largest stem diameter at 567.27 mm, and the highest chlorophyll content at 36.858 SPAD units compared to the control treatment. Boron nanoparticles at 15 mg/L resulted in the maximum leaf area (158.88 cm²), stem height (419.29 cm), stem diameter (579.64 mm), and chlorophyll content (38.656 SPAD) compared with the control. Nano iron at 6 mg/L resulted in the maximum leaf area (173.92 cm²), stem height (466.83 cm), stem diameter (678.70 mm), and chlorophyll content (45.465 SPAD) compared with the control. Combined effect of two factors resulted in the most favorable results. Combined effect of three factors resulted in optimal results with leaf area 175.00 cm², stem height 474.00 cm, stem diameter 694.00 mm, and chlorophyll content 43.753 SPAD. In contrast, the control resulted in the lowest values with leaf area 121.33 cm², stem height 277.33 cm, stem diameter 341.50 mm, and chlorophyll content 26.243 SPAD